DIAMETER: Diagnostics for Malaria Elimination Toward Eradication
The goal of the DIAMETER team is to catalyze and support the rapid development, commercialization, and implementation of the most promising, cost-effective, and impactful diagnostic technologies for malaria elimination. Because the last malaria reservoirs may be the hardest to detect, PATH Diameter aims to address this global challenge in malaria.
Many countries that have implemented successful malaria control programs are now close to achieving the goal of malaria elimination. In these areas, a significant portion of infected individuals have minimal or no symptoms but are still capable of transmitting malaria. Additionally, many of these cases are not detectable by existing rapid diagnostic tests (RDTs). New, highly sensitive point-of-care tests are needed to identify these final reservoirs for malaria in near-elimination settings.
The aim of DIAMETER is to enable access to the most appropriate malaria diagnostic tools to support malaria elimination tactics. Starting in 2012, PATH received funding for the concept and technical feasibility stages of the development of a Plasmodium falciparum (Pf) ultrasensitive rapid detection test (uRDT). During the concept stage, the DIAMETER team conducted technology landscapes; a user needs analysis; and a market analysis. In close collaboration with the foundation and a technical advisory group, the DIAMETER team identified the histidine-rich protein 2 (HRP2)-based uRDT as a high-priority investment and developed a preliminary target product profile for an HRP2-based uRDT with a 10x improved limit of detection over existing commercial rapid diagnostic tests. PATH also began conducting research into biomarkers for Plasmodium falciparum infections to guide the development of new diagnostics. Using clinical samples collected from asymptomatic individuals, PATH measured HRP-II, lactate dehydrogenase (LDH), and parasite nucleic acids throughout the course of Plasmodium falciparum infection and applied this information to measure the sensitivity of various tests commercially available and in development.
In April 2017, a major technological breakthrough in high-sensitivity rapid testing for malaria was launched: the Alere™ Malaria Ag P.f: an in vitro, qualitative, and ultrasensitive test developed by Alere™ to aid in the diagnosis of Plasmodium falciparum (Pf) malaria infection. It has a greater than tenfold improvement in detection of Pf HRP2 antigen in infected human whole blood, which will enable better identification of low-density parasite infections. PATH, FIND, Alere™, and the foundation are currently seeking to conduct studies that demonstrate detection of low-density parasite infections and programmatic impact studies that demonstrate the value of the test in elimination strategies.
PATH and partners are continuing evaluations of other highly sensitive tests for malaria, including a Plasmodium vivax RDT. This will also include the characterization of biomarkers in clinical P. vivax-infected specimens. Other test options that are currently under evaluation are a Pf HRP-II ELISA, a Pf HRP-II/Pf LDH RDT, and a pan-malaria RDT.